The opposite of play is not work. The opposite of play is depression.
Madness string 111450
The tendency of the tech industry to re-use certain words ('message', 'class', 'hierarchy') in radically different contexts makes it difficult for us to discuss these concepts with clarity. If we simply invented new words for new concepts, as Isaac Newton did when he invented the word 'gravity', we would have a better vocabulary for discussing the radical innovations brought to us by computers.